In conventional technique, a torsional vibration damper pulley has been used to damp or attenuate the torsional vibrations generated during the operation of an internal combustion engine. The damper pulley is driven by the internal combustion engine. In a front end accessary drive (FEAD) system, the damper pulley is also used to provide power to front end accessories, such as an alternator, a water pump, and an air-conditioning compressor. In addition, the internal combustion engine utilizes a balance shaft assembly or adds timed force unbalance on flywheel to attenuate the vibration caused by the movement of a connecting rod.
With the development of the technology, for some hybrid vehicle employing a high voltage battery, an electronic water pump and an AC conditioner compressor may be used to improve thermal efficiency. Thus, it is possible to integrate a vibration damper into an engine block under non-FEAD circumstance. DE patent 536929C discloses a torsional vibration damper disposed on a crank web. U.S. Pat. No. 6,883,487B2 discloses a torsional vibration damper integrated into a crank web. However, the torsional vibration dampers disclosed in the two patents have complicated structures, which includes a number of springs and couplings.